Apple has acknowledged that some of the company's iPhone 8 devices have a manufacturing defect, which can cause some units to freeze or not turn on at all.A "very small percentage" of devices contain logic boards with the manufacturing defect, the company said on its website.It is unclear how many units are affected, but Apple said the devices were sold between September 2017 and March 2018 in the United States, as well as in Australia, China, Hong Kong, India, Japan, Macau and New Zealand.The replacement program does not apply to iPhone 8 Plus or any of the other models.Users can check to see if their device is affected by entering their unit's serial code number on the company's website.If the device is impacted, Apple will replace the logic board for free.Apple says if a customer's phone has damage — such as a cracked screen — that could impact the repair, the user would need to resolve that issue first."In some cases, there may be a cost associated with the additional repair," the company said.A user can find the device's serial number in: Settings > General > About > Serial number. Users can long-press on the serial number to copy it.The number can be pasted into Apple's replacement program website. If the device is affected, Apple will explain the options the user can take.

Apple has acknowledged that some of the company's iPhone 8 devices have a manufacturing defect, which can cause some units to freeze or not turn on at all.

It is unclear how many units are affected, but Apple said the devices were sold between September 2017 and March 2018 in the United States, as well as in Australia, China, Hong Kong, India, Japan, Macau and New Zealand.

The replacement program does not apply to iPhone 8 Plus or any of the other models.

Users can check to see if their device is affected by entering their unit's serial code number on the company's website.

If the device is impacted, Apple will replace the logic board for free.

Apple says if a customer's phone has damage — such as a cracked screen — that could impact the repair, the user would need to resolve that issue first.

"In some cases, there may be a cost associated with the additional repair," the company said.

A user can find the device's serial number in: Settings > General > About > Serial number. Users can long-press on the serial number to copy it.

The number can be pasted into Apple's replacement program website. If the device is affected, Apple will explain the options the user can take.